1. Field of the Invention
The present invention relates generally to fire prevention, and specifically to devices and methods for preventing the destruction of dwellings and other roof-containing structures from fires caused primarily from burning debris, especially embers from brush/bush fires, by co-segregation of atomized fluids and buoyant burning debris using perimeter fluid delivery and heat convection.
2. Background Information
Each year, the cycles of little rain followed by a long dry spell have lead to the accumulation of large amounts of dry brush and other vegetative combustibles. Under such conditions, dried trees and bushes become ideal fuel for wildfires. In regions with perennial dry seasons, these conditions produce fires that cause billions of dollars worth of damage.
With wildfires in the West seemingly becoming more frequent and destructive, there is a growing concern that climate change associated with global warming might be creating more fertile environments for these fires. In California, a major concern is centered on the effects of the Santa Ana winds. The Santa Ana winds are strong, extremely dry offshore winds that characteristically sweep through in Southern California and northern Baja California. They can range from hot to cold, depending on the prevailing temperatures in the Great Basin and upper Mojave Desert. However, the winds are noted most for the hot dry weather that they bring in autumn. With extremely low to no humidity and high temperatures, all that is necessary is a spark, and with the strong winds fanning the flames, in no time there is a full scale wildfire.
There is a widely held belief that fast moving wildfires explode houses into flames, burning them down in minutes, however, this not borne out by scientific observation. Typically, the majority of houses destroyed in wildfires actually survive the passage of the fire front, only to burn down from ignitions caused by buoyant burning debris. In fact, showers of burning debris may attack a building for some time before the fire front arrives, during the passage of the fire front and for several hours after the fire front has passed. This long duration of attack, to a large extent, explains why burning debris is a major cause of ignition of roof-containing structures.
Further, video footage of burning buildings caused by wildfires shows that a fire usually starts from the roofs and attics, then propagates downward to the support, and then collapses onto the lower section of the structure. The most common culprits for the observed vulnerability of roofed-structures are interstices between tiles and/or shingles and the openings for ventilation. These interstices and openings provide an entry path for flying embers to ignite structural items that make up the roof (i.e., plywood panels, support tresses, and felt liners), as well as fuels available in attics (e.g., old papers, clothing and the like).
While systems exist claiming to prevent fires on roof-containing structures, they all must be placed on or over the top or apex of the roof, and/or use copious amounts of water (see, e.g., U.S. Pat. Nos. 4,330,040; 5,263,543; 5,692,571; 6,679,337). What is needed is a system that douses embers as they enter interstices and openings available on roofs, which embers escape systems that provide water only in a downward direction along the slope of the roof via gravity. The present invention fulfills this need, and at the same time conserves water use.